Fig. 7. Microporosity can be a predictor of the material provenance within the parent body.

The mean compaction of the particles that make up an individual rubble-pile aggregate in our simulations is a measure of the microporosity of that aggregate. We show the mean compaction for all four cases described in Table 1. The color of each scatter point represents its associated simulation: purple, green, yellow, and red circles are aggregates from the Q/Q* = 0.64, 1.07, 1.48, and 1.98 cases, respectively. We find that the change in a rubble pile’s microporosity relative to that of the parent body material (y-axis) is an indicator of that material’s original location from within a parent body (x-axis, parameterized by the mean source region of all particles making up the rubble pile, ${\overline{R}}_{\mathrm{source}}$, normalized by the parent body radius, $R_{\mathrm{parent}}$), regardless of the energy of the family forming impact. This is illustrated by the black dashed line, which is a linear fit to data from all simulations, and has the form C = (1.68 ± 0.02) ${\overline{R}}_{\mathrm{source}}/R_{\mathrm{parent}}$.